I’ve been running a set for 3 years. They are very easy to service – a strength in their design. The damping unit is fully contained within the upper and thus it doesn’t get contaminated with the elements.
The TS8 axle bolt is more durable than a Rockshoxx Maxle (the handle pins wear out on the Maxle). Fox has the best axle lever of the three in my opinion.
I find TS8 ride to be stiff over fast rough terrain, but good over big bumps. Lowering air pressure and adjusting rebound helps only a little. I think it could be improved with lighter shock oil (2.5W vs. 5W) but not tried it yet.
Potential longer-term maintenance issue with the axle design (uses M14x1.0 threads). The thread seat is not removable. I don’t know what grade alloy it is but it isn’t stainless steel. Thus, the threads will wear out from repeated installation and removal of the bolt. Thus you either have to install a helicoil/v-coil style thread insert or replace the lowers. In my case the threads wore out while the oil seals and bushings are still original and serviceable.